1. Technical Field
This invention relates generally to surgical cutting instruments, and, more specifically, to a surgical cutting tool having a vacuum clearance capability for use in connection with rotary cutting instruments in the field of hair transplantation.
2. Background
Many people experience over time a gradual thinning of hair with age. Men in particular are prone to receding hairlines and the loss of hair from the crown of the head, so-called male pattern baldness. Many men and women suffering from hair loss turn to hairpieces or wigs in an effort to retain a youthful appearance.
Those wanting a more permanent solution to hair loss have undergone conventional treatments for hair restoration. Preparations containing minoxidil have been shown to be effective, particularly in younger persons, but they must be applied twice a day and use must be continued indefinitely as hair loss will recur if the application is stopped. In some users minoxidil causes skin irritation.
Though hormone therapy has been prescribed for certain types of hair loss, as with other hormone treatments it is not without risk.
In an effort to achieve more significant results, hair transplantation has become an important treatment for hair loss. It involves the relocation of plugs of skin from parts of the scalp containing active hair follicles to bald areas. The process includes preparing a "recipient site," i.e. that portion of the scalp where a skin plug is removed, in the bald areas and transplanting an active hair follicle into the recipient site.
Another procedure, termed scalp reduction, may also utilize hair follicle transplantation. In scalp reduction the scalp is tightened so that hair bearing skin from the back and sides of the head is pulled toward the crown. Hair may then be transplanted to the remaining bald area at the top of the head.
Heretofore the most common method to prepare recipient sites for hair follicle transplantation has been to stab the scalp with a non-cannulated biopsy type punch for the purpose of removing cylindrical tissue plugs. This type of cutting instrument has a tubular design at the cutting tip and employs a vent hole in its side to facilitate removal of small plugs from the scalp by relieving pressure build-up. The punch, once filled with plugs, is generally handed to an assistant who must clean out the punch of plugs removed. As can be imagined, this is a laborious and offensive task. The surgeon continues the process with another clean punch.
Recent attempts have been made to somewhat automate the hair transplantation process. Certain punches have been modified with a steel shank to fit into the chuck of a motor driven power source, such as a dentist's drill, to make preparation of recipient sites easier. Other systems have been developed to more completely automate the entire process of hair transplantation. These systems utilize a surgical cutting tool coupled to a vacuum source designed to cut tissue plugs and remove them by suction.
Examples of conventional surgical instruments and systems are described in U.S. Pat. Nos. 3,867,942; 4,476,864; 5,133,360; 5,172,702; 5,403,317 and PCT International Publication WO 94/07433.
One drawback to existing systems, particularly those attempting to utilize vacuum pressure for tissue plug evacuation, is the tendency of cutting tools to clog with debris. It has been found difficult to provide rotary cutting systems utilizing vacuum suction to evacuate tissue plugs from the cutting instrument which do not have this tendency.
It is therefore an object of the present invention to provide a cutting tool having vacuum clearance capability which can be used either manually or in rotary instruments and which can more effectively evacuate tissue plugs cut from the scalp.
It is another object of the present invention to provide the surgeon a single cutting instrument that can be used to complete work in the entire recipient area without a tiresome exchange of instruments.
It is a further object of the present invention to provide a method of making such a surgical cutting instrument that provides for new various sizes of cutting tips.